半固态7075+1.7TiC铝合金二次加热工艺的研究  

Study on Reheating Process of 7075+1.7TiC Al Alloy in Semi-solid State

作　　者：刘慧敏[1,2] 刘丽[1] 许萍[1] 

机构地区：[1]内蒙古工业大学材料科学与工程学院,呼和浩特010051 [2]内蒙古新材料工程技术中心,呼和浩特010051

出　　处：《材料工程》2010年第11期17-20,25,共5页Journal of Materials Engineering

基　　金：国家自然科学基金资助项目(50661003)

摘　　要：在不同的二次加热温度和保温时间条件下,对喷射沉积7075+1.7%(体积分数)TiC铝合金的二次加热工艺进行研究。采用扫描电镜观察合金的二次加热组织,利用平均截线法统计晶粒尺寸。结果表明,在580℃进行二次加热时其晶粒长大非常缓慢,温度提高到600℃后,晶粒长大速度有所提高。在580℃和600℃分别保温60min后,合金对应的平均晶粒尺寸为14μm和20μm。二次加热温度超过610℃后晶粒长大速度显著提高,并出现明显的局部重熔现象。对应620℃保温30min的平均晶粒尺寸53μm。说明在上述条件下得到的半固态坯料仍保持细小等轴晶组织的特征,能够满足后续的触变成形工艺对合金组织的要求。The microstructures of in-situ reactive spray formed 7075＋1.7%TiC Al alloys at semi-solid state were observed using SEM.The grain sizes were measured using a mean linear intercept method and the effect of in-situ TiC particles on grain growth in the two-phase（liquid ＋ solid） region of 7075 Al alloy were analyzed.It was shown that the grain growth was very slow at 580℃ and when the reheating temperature was up to 600℃,the grain growth velocity was increased gradually.The average grain sizes were 14μm and 20μm at 580℃and 600℃ for 60min.when the reheating temperature was up to 610℃,the grain growth velocity was increased evidently,and part reheating was appeared.The average grain sizes were 53μm at 620℃ for 30min,which indicates that in-situ reactive spray formed 7075＋1.7%TiC Al alloy can keep fine and equiaxed characteristic,and meet the requirement of thixoforming on microstructure of alloy.

关 键 词：喷射沉积 半固态7075+1.7TiC铝合金 二次加热 晶粒长大 

分 类 号：TG146.21[一般工业技术—材料科学与工程]